Electrical connection boxes of the type described herein hold various electronic circuits and components, and also serve as branching points for wire harnesses.
Referring to FIGS. 8 to 12, main unit 41 of the electrical connection box includes mounting surface 43 on upper surface 42. Positioning sections 44 are located at the four corners of mounting surface 43. Engagement locks 45, spaced apart from each other, are adjacent side surface 52 and between two positioning sections 44. They project from mounting surface 43, as does male connector 46.
Circuit unit 47 is provided with bottom surface 48 which corresponds to mounting surface 43. A female conductor (not shown) projects from bottom surface 48 and mates with male connector 46. One of cassette locks 51 projects from each of side surfaces 50. These cassette locks fit with engagement locks 45 to secure circuit unit 47 to main unit 41. In this position, male connector 46 is engaged by the female connector of circuit unit 47 to form an electrical connection.
Engagement locks 53 are spaced apart from each other and project toward engagement lock 45 of main unit 41. Holder 54 comprises main unit attachment section 55 and connector attachment section 56. Attachment section side surface 58 of attachment section 55 is a flat surface and two cassette locks 59, spaced apart from each other, project from the side surface. The upper end of side surface 58 is at the same height as the upper ends of cassette locks 59. When cassette locks 59 are within engagement. locks 53, thereby retaining holder 54 on main unit 41, insertion space A is formed between main unit 41 and holder 54 by side surface 52, engagement lock 53, side surface 58, and cassette lock 59. Opening 61 is located at the center of connector attachment section 56.
Diagnosis connector 60 includes a plurality of connection terminals 62 at the lower end thereof. When the diagnosis connector is in place, connector terminals 62 are in electrical contact with wire harness 63. Wire harness 63 passes through insertion space A and extends out in the direction of circuit unit 47.
Due to the construction of positioning sections 44 and engagement locks 45, it is possible for portions of wire harness 63, having been passed through insertion space A and extended out toward circuit unit 47, to stray onto mounting surface 43.
This is particularly shown in FIGS. 8 and 10. If circuit unit 47 is then mounted on main unit 41, those portions of wire harness 63 which are on mounting surface 43 will be trapped between circuit unit 47 and main unit 41 or between circuit unit 47 and engagement lock 45. This may interfere with the electrical connection between circuit unit 47 and main unit 41; in addition, this malfunction can cause the application of excessive force to wire harness 63, resulting in distortion or even breakage thereof.
Moreover, side surface 58 of holder 54 is usually flat, making insertion space A very narrow. When the harness is extended through insertion space A, there will be a tendency to cause the harness to bend in an unforeseeable direction. As a result, it becomes difficult to draw out wire harness 63 when completing the connection. Therefore, there is a need to restrict the wire harness so that it will not move onto mounting surface 43.